\documentclass[letterpaper,10pt]{article}
\usepackage{graphicx}
\begin{document}

\begin{figure}
\centering
\includegraphics[scale=0.5]{cyclelen.1.mps}
\end{figure}

\begin{figure}
\centering
\includegraphics[scale=0.5]{brent.1.mps}
\end{figure}

\end{document}
